Method and means for braking vehicles



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C. L. STOKES METHOD AND MEANS FOR BRAKING VEHICLES Original Filed April 23. 1925 2 Sheets-Sheet 1 D c 5; A $1 49] April 24, 1928.

1,667,016 c. L STOKES METHOD AND MEANS FOR BRAKING VEHICLES Original Filed April 255, 1925 2 $hets-$heet 2 INVENTOR atented Apr. 24, 1928.

CHARLES L. STOKES. OF LOS ANGELES, CALIFORNIA, ASSIG'NOR OF ONE-HALF 'IO GEORGE L. ERTZ, 015' LOS ANGELES, CALIFORNIA.

METHOD AND MEANS FOR BRAKING VEHICLES.

Application filed April 23, 1925,'Serial No. 25,345. Renewed August 22, 1927.

My invention relates to improvements in methods and apparatus for applying a braking force for slowing down and/or stopping a vehicle.

Theiprincipal object of my invention is to utilize a brakingtorce generated within an internal combustion engine carried by a vehicle and to apply said force through the mechanism connecting the vehicle wheels with the engine. v I

Another object of my invention is to automatically control the application of said braking force by automatic means responsive to engine speed and load .when deceleration and/or stopping is desired. 1

Other objects in general are to provide improvements upon the invention described in an application for patent by George L.

Ertz S. N. 20,126 filed April 2, 1925, and

these improvements I am now. enabled to adapt at minimum cost and maximum efficieny.

Referring to the drawings in which the same numbers indicate like parts Fig. 1 is a view showing the application of my invention to an internal combustion engine in an automobile.

Fig. 2 is alvertical section and part view along the lines 2-2 of Fig. 1.

Fig. 3 is an alternative construction of part of Fig. 1.

Fig. 4 is a diagram illustrating the valve timing of the engine in Fig. 1.

i Fig. 5 is an alternative construction of the apparatus shown; in Fig. 2.

Referring particularly to Figs. 1, 2, 3, and 4. an internal combustion engine 1, which is of the' well known four cycle type, is equipped'withian'exhaust ipe 2 and an intake manifold 3 to which atter is attached any well known make of carburetor 4 'for supplying engine 1 with air and liquid fuel, or a combustible mixture. Thesupply of combustible mixture from 4 through 3 is con trolled by the usual butterfly valve 5which manipulation. The valve 5'is held on a spindle 6 suitably journale'd inthe mixing chamber walls of carburetor 4 and on one endof the accelerator rod 8 is fiexiblyjoined for k-ontrollirig the speed of engine 1 by means of a button 9. The rod i iii a;pivoted bearing 15 and normal posilss tionof the 8 .as-shown,',wl rereby the.

. bracket 16 to the flange of carburetor 4.

14for operating a valve 21 controlling the is also a balanced valve which permits easy spindle 6 is fixed a throttle arm 7 to which- 8 is slidably mounted valve 5 is normally held substantially closed for idling conditions by a spring 11 connected'between suitable positions on rod 8 and part of engine 1. v

On the other end of spindle 6 a second arm 12 is fixed having an enlarged portion 13 through which passes a. rod 14 which forms an extension of the armature of a solenoid 15 which may be suitably fastened by a The armature 14 may be constructed of brass up toand including a co1la-r17 fastened thereon and designed to contact with the arm 13 on one face thereof so that when current is'passed through the windings of solenoid 15, the armature 14 will open the valve 5 but at thesame time when no current is passing through 15, the valve'5 will be solely manipulated'by the will of the driver by means of the accelerator rod 8. The end of armature 14 is linked through .a lever 18 to a second balanced throttle valve 19 placed in the exhaust pipe 2 and an extension 20 is firmly connected to armature admission of atmosphere through ports 22 and 23 to the interior of the float chamber 24 y of carburetor 4'and a spring 25 serves to normally retain valve 21 off its seat in port 23. It will be noted that upon opening the valve 5 by the movement of armature 14, that the bevelled edge 26 on the end of ex-' tension 20 is so designed as to seat the valve 21 firmly in-port 23 thereby cutting otr' the supply of atmosphere throu h theport 22 and thus cutting off the supply of fuel passing from the float chamber 24 through the passage 27 to the fuel orifice 28 whence it is normally mixed with air through the port 29-and supplied to engine 1 by itssuction.

A foot brake lever 30.i-s pivotally' connected to a rod 31 slidably mounted in a pivoted bearing 32* Jand a depression of pedal 30. causes the end of rod 31 to make a contact between spring terminals 32 and 33, terminal 32 being mounted on and insulated from the manifold 2 and terminal 33 being mounted 'on and insulated from thecasing' of solenoid At a suitable point in manifold 2 between the valve 5' and-engine 1 isplaced a ipe 34 connected at one end to the interior 0? a casing 35, The other end of easing 35is con nected by a pipe 36 to a point in the mixing chamber of carburetor 4 between the valve 5 110 on its end a metallic-contact point 46 adaptgins through a separate airand fuel passage 8! and the atmosphere inlet 29 and this point past upper dead center and the inlet valve ma be at the constriction or throat, of the closes at IC which is about twenty degrees or inary venturi 37, with which most carpast bottom dead center. 'buretors are equipped. In the position of thepistons as assumed A piston 38 moves in one end of casing 35 above, the vacuum induced b the iston in 74 responsive'to on no vacuum applied therecylinder Bis' serving normal y to raw liqto through the pipe 34 and a spring 39 noruid fuel through 28 and air through pasmally-returns piston 28 to a predetermined sage 29 to the interior of cylinder B and the position. A rod 40, made of-non-conducting, amount of said mixture, which governs the material, is fastened to iston 38 and on the speed of the engine 1, will be controlled by 7: end of rod 40 is place a metal contact 41 the position of throttle 5. Depending on adapted to close a circuit between the spring the position of throttle '5 will depend the dcterminals 42. In the other end of casing 35 grees of partial vacuum existing on either is placed a second piston 43 which is responside of throttle 5. v J5 sive to the engine induction vacuum applied For instance, if engine 1- vis idling, throttle 80 through pipe 36.. A spring 44 normally re- 5 will be substantially closed and there will turns piston 43 to a predetermined position. be about twenty inches of mercury vacuum 7 and a rod 45, made of non-conducting mateon the engine side of throttle 5, the idling rial is firmly fastened in piston 43 and has mixture being generally'supplied to the en-' .ed to close an electric circuit between spring not shown). Atthis time when throttle 5 terminals 47. Spring terminals 42 are is closed, there will be substantially atmospassed through insulation in casing 5, as are pheric pressure onthe atmosphere side of spring terminals 47,, and said terminals are throttle 5, therefore the 'en e vacuum to 85 connected on one side to' a lead wire ,48 fasany degree will be applied t rough pipes 34 W tened toone pole of a storage battery 49, the. and 36 for the movement of pistons 38 and I other pole 0 which is ground at 50. On 43 respectively. I Y the other side of casing 35, said spring ter- As the th'rottle5 is opened'alfan increasminals are connected in parallel with the ing'degree towide open, the speed of engine a lead wire 48 which then passes through the 1-will reach a maximum at light loads and 95 windings of solenoid and thence to the thereafter the speed-of en 'ne 15will decrease 'spring contact 32. The brake pedal is as more load is applied t ereto, such as for grounded at 51 and thus itwill be seen that instance 'when the automobile is climbing a 7 when the circuit is closed bymeans of the steep grade. At all 'wide open positions: of

' rod 31 forming a contact between springs 32 throttle 5, the partial vacuum oneither side 9 and 33 that a current will energize the sole,- thereof is substantially equal and therefore no1d 15. An air vent 52 is provided-in casthesame will be transmitted equally through 1ng35in order to permit the free movement pipes 34 and 36 and in the usual four cycle of p1stons' ,38' and 43 responsive to the 'vacen ine, with the throttle wide open, said par-.

'. (0 uum of engine 1. A wire 53 is connected to tia vacuum will range from aboutsix inches 1 thespring 33" and leads fromany part of the of mercury to one-half inch of mercury gnltion system of engine 1 for short circuitwhen the engine speed passesfrom a maxi- 1n the same, 1f deslred. mum toa minimum, but varying, of course, n theoperation of four cycle internal with carburetor constructions. 45 combustlon engmes, such as my, invention is Therefore the engine vacuum below throt- 11 particularly adaptedfor, and assuming that He 5 is 'an indication of engine load and the an engine of that type has four cylinders, "vacuum above throttle 5 is an indication .of

i each having intake and exhaust valves, said engine speed.

. usual firing'order of said'cylinders is A, C, describe cylinders are designated A, B,C and D. The In'coxgunction with the factors as already I am now enabled to apply a 11 c D, B. Let 1t be assumed that the piston in brakin' force to the vehicle carrying engine cylinder A is at upper dead; center on its 1 whic will then be normally available acexh'aust stroke. Cyhnder 'D null then be at cording to the partial vacuum 'generated'by full com resslon, cyl nder G wlllbeat botengine 1 at a particular speed and this op- 1 tom dea .center on its power -strokeland c leration is performed as follows 12 I nderB will be at bottom dead center on its If it be assumed that throttle 5 is wide suction stroke. open, the button 9' will be fully depressed.- Let 1t also be assumed that the valve timand spring 11 will brain-tension. Thezair mg for each of said cylinders'is as shown in ports 22 and 23 will be fullysnpen thus en- 00 Fig. 4 wheremthe exhaust closes at E0 suring a" free flow offuel through passa e 12 wh1ch 1s'abput five degreespast upper dead *2? and orifice 28.. The bah pedal 30. will canton-the. mlet valve opens at,-IO which is be held, in its normal as by a about ten degrees past upper dead center, 30' and the rod 31 m be out of contact the exhaust valve opens at ;E0 which, is with the springs 32 and 33. At this time theql'about one-hundred and thirty-five d before mentioned vacuum of six inches of la 47 but the contact 41 will not be in engagement with the spring 42. Therefore there will be no currentflowing from storage battery 49 through the solenoid because while the circuit will he made at 47' the same will be broken between contacts 32 and The valve l9'will be normally as shown permitting free passage of exhaust gases through exhaust pipe 2 to atmosphere.

If now it be desired to decelcrate,- the release of the foot from button 9 will immedia-t-ely close valve 5 and the vacuum above 5 Wlll jump from twenty inches 01' mercury to about twentysix inches of mercury due to the high rate of piston speed and this vacuum will then cause piston 3-8 to jump and engage the contact 41 between springs 42. At the same time the closing of throttle 5 diminishes the vacuum below the same to substantially atmospheric pressure whereby the contact 46 is disengaged from the terminals 47.

It now the brake pedal 30 be depressed a predetermined amount for slowing the automobile, a contact will be made between the rod 31 and the terminals32 and whereby current-from the storage battery49 passes through 48, 42, 41, to the windings of sole noid 15 thence to the terminal 32 thence through the rod 41, and the foot pedal 30 to the ground 51. i

The sudden energizing of solenoid 15 thereupon immediately causes a jump of the armature 14 whereby the throttle 5 will be thrown wide open, the valves 21 and 19 will be fully closed, the accelerator rod 18 also being fully depressed against the action of spring 11.

'In this'manner by the reopening of valve 5, a partial vacuum of predetermined degree will be again equally applied through pipes 34 and 36 to the pistons 38 and 43 respectively whereby 41 will be disengaged from terminals 42 and-the contact 46 will be reengaged between theterminals 47 "thusensurin the continuity of the passage of current or maintaining the energizing of solenod 15.

The closing. of port 23 thus prevents the access of atmosphere to the interior of float chamber 44 so that "the engine vacuum now 7 being applied to. orifice 28 is inetl'ective for withdrawing liquid fuel therethrough and thus-solely pure air is supplied to the inlet 29, and manifold 3 to the cylinders of en'- gine 1.

Thus the cylinders A, B, O and D on their intake-strokesare supplied solely with pure air and this air will'be su plied under a comparatively low degree 0 vacuum. The

\ atmospheric pressure and the amount of air is then compressed on the compression stroke of any particular cylinder and the work of compression is returned to the engine on the expansion stroke of the cylinder until the exhaust valve opens at E0. The opening of the exhaust valve at 130 then permits the expulsion of part of the air to the exhaugt pipe 2'but the same is trapped therein due to valve 19 being closed and therefore on the exhaust stroke of any particular cylinder a predetermined degree of compression will'be obtained in the exhaust pipe 2.0fhparticular cylinder, which compretjsion is a back pressure against the rotation of the parts of engine 1 and thus a braking force is automatically generated for decelerating the automobile, it being assumed of course, that the clutch connecting engine- 1 with the rear. wheels and the usual transmi sion gears are in engagement.

If it be assumed that. the braking force is applied in cylinder A at the top of its compression stroke, it will be noted that the exhaust valve on cylinder B will be open to the exhaust pipe 2 therefore there will be overlapping discharges of compressed air from one cylinder to the other so that the compression stroke in each cylinder will really notstart at a sub-atmospheric pres-- cure but may be adjusted to start at a superthis pressure-may be calibrated by any particularly desired-annular clearance between the circular butterfly valve 19 and the interior of exhaust pipe 2.

It will thusbe seen that the braking force maybe applied through the compression of air in the engine and additionally through the brakes connected to foot pedal 30(not shown) and foot pedal 30 may be calibrated for causing the rod 31 to close/the contacts 32a-nd 33 with any desired degree of travel. With the valve 5 wide open, due to the action of solenoid 15, the deceleration of en'-' gine l will'continue to a point where the vacuum applied to piston 43 is inxufiicient to retain the contact 46 in engagement with the terminals 47 whereupon the circuit will be broken thus causing solenoid 15 to be deenergized whereupon valves 19 and 21 will open and valve 5 will close to the idling position and the time for closing valve 5 in this manner may be calibrated for any par ticular engine speed so that engine 1 will never remain dead at that particular speed.

At the same time the same valve action will ensue at any period of deceleration upon the release of foot pedal 30 so that the automobile may be decelerated' partly or wholly and engine 1 will die for a predetermined p'e'riod only.

If desired the terminal 33' may be con-' nected to the lead wire 53 for also short circuiting the ignition of engine 1, butin sions are made, as have been shown, for cutting ofi the sup 1y of liquid fuel through ori ca 28 and 0? course it is obvious that valve 21 may be alternatively placed so as to directly and positively cut off the supply of liquid fuel through the passage 27 but in either case the-same result is achieved i. e., cutting ofll the flow of liquid fuel through orifice 28 responsive tothe engine vacuum. Also'it will be noted that in place of the pistons-38 and 43 and the springs 39 and 44 that the 'wellknown' form of metal bellows closed at one end may be provided and under certain conditions this may be desirable to prevent the action of dust through the port 52 whereby the action'of pistons 38 and 44 would be retardedbut many equivalents are apparent to those skilled in the art.

An alternative construction is shown in Fig. 3 whereby the valves 18, 18", 18 and 18 are individually supplied for governing the individual cylinders. A, B, C, D respectively and in such case said valves will be large portion of exhaust pipe 2.

controlled through suitable linka es connect-I.

ed to the armature '14 in any desired fashion to operate as already described and it will be noted that where the structure shownin Fig. 3 may be used, a higher degree of compression braking force may be obtained in said cylinders because ofthe reduced compression space due to the elimination of In the structures alreadydescribed it can .be seen that the elements include generally the use ofengine induction. vacuum for controlling a balanced valve by means of a sole? noid whereby lpure air may be supplied to an..eng1ne for raking pu oses' and so constituted that the engine-wi 1 never be killed g per minute.

below a predetermined number of revolutions In another construction shown in Fig. 5, I illustrate like results which may be obtainedmechanically without the interposition of electrical influences but in which I utilize the effect of engine vacuum as already described as a control factor.- i

i Similar vacuum responsive devices are provided in casings ..35" and 35" which are respectively joined'above and' below the valve 5 and the -rods-.40- and'45" are inadeof metal and respectively extend outside from 35? A finger 57 is on 405 5nd a finger 58 is-adjustab yifastened on more forsubstantiall contacting with a disc 59 which has 9, ha -60 adapted to slide on the rod 14 which in the presentflcase is directly. 1

connected through the valve 19 and is provided with aneccentriciGl for actuating the valve-21, with an eye 62 adapted to hold a hook63 connected withthe' arm 12 and with eration by the foot edal 30 through a rod' 69,-washers and 1, a spring 72 therebetween and an adjusting nut 73. The bell crank 67 has a third arm 74 adapted to go up against a stop 75 upon apredetermined depression oftpedal 30.

The operation of this device is as follows: Similar instrumentalities as already de scribed are provided in casings 35 and35" whereby at predetermined engine vacuums, one-of the fingers 57 and 58 will hold the hub 60 in position over the key 64, 7 a

When the foot pedal 30 is thende ressed for deceleration, it will seen that t e rod 69 will be pulled against the sprin 72 and washer 70 to move the bell crank 6 a predetermined distance when arm 74 willcome upagainst stop 7 5. This movement of bell crank 67 will'cause 68 torotate the hub 60, thereby rotatin the rod 14 and throwing the vulva 5 wide of spring 11. The ccentric (or cam) 61 will also be revolved to lose the valve 21 and the open against the tension valve 19 will berotatedto close exhaust rate of deceleration,- or upon stopping the automobile, the vacuum a plied to casings 35- and 35" will be such t at the recession of fingers; 57 and 58 will cause the disengagement of key. 64' from keyway 6,5 whereupon.

the tension ,ofspring 11 will cause the closing of valve 5 irrespective of 30 is depressed or not..

Thereafter the movement of accelerator rod 8 will operate the valve 5 without motion of rod 14.

In this structure it should particularly I noted that thesame is designed for the operation of automatic braking efiect-uponj a whether footpedal r minimum depression of'foot pedal 30' when the arin 74 will come into engagement with the st0pr75 and thereaftergany further de-.' pression ofpedal 30 for applying the mechanicalbra e, -will permit t e -rod .69 .to .slide through one arm-of bellfcrank 67 as far as may be desired and in this manner asinrgle structure of low cost may be had tooh- It'will noted especially thatgthe valves 5 audit) are balancedvalves, i. e., they are of circular form, rotated centrally so that gaseous pressures are balanced at any degree of opening, thus rendering manipulation easy, Therefore the solenoid will require very little current, if used, and if the structure of Fig. 5 be used, the valves will be responsive to low degrees of vacuum.

free of the key 64 at the proper periods. I claim 1. The method of decelerating a vehicle impelled by an internal combustion engine,

which comprises supplying a gaseous fluid to an engine rotatedby the inertia of a vehicle,

creating a back pressure in the engine by throttling the discharge of the gaseous -fluid therefrom and governing said back pressure by the engine induction vacuum.

2'. The method of decelerating a vehicle impelled by aninternal combustion engine, which comprises supplying-a gaseous' fluid at substantially atmospheric pressure to an engine. rotatedby the inertia of a vehicle,

creating-a back pressure in the engine by throttling the discharge of the gaseous fluid therefrom and governing said backpressure by the engine induction-vacuum.

3. Ina vehicle impelled by an internal combustion engine, means. for decelerating said vehicle including a valve actuated-by the engine. suction for throttlingthe exhaust of'the engine.

4. In a vehicle impelled by .an internal combustion engine, automatic means for decelerating said vehicle including a valve actuated by the engine suction for throttling the exhaust of the engine.

5. In a vehicle impelled by an internal combustion engine and having a plurality of wheels controlled by brakes, means for decelerating the vehicle including a lever for applying the brakes andadditional means actuated by the engine induction'vacuum operative on movement of the-lever for preventing power'impulses in the engine.

6. In combination, a wheeled vehicle impelled by an internal combustion engine,

' means for applying the power of the engine wheels in conjunction with the movement oi:

said first braking means; said last mentioned means belng operated by the engine inductron vacuum.

7. In a braking system for vehicles, an in- The spring 76 serves to draw the hub exhaust passages, athrottle in each of said passages, a lever, and means automatically controlled by the suction of said engine for causing the opening ofsaidthrottle in said intake'passage and the closing of the throttie in said exhaust passage upon the movement of said lever.

8. In a braking system for motor vehicles, 'an internal combustion engine having an exhaust passage, a throttle in said passage, a brake lever, and means automatically controlled by thesuction of said engine for opcrating the throttle in said. intake passage upon a predetermined movement of said lever.

.sage, a fuel chamber. having a vent, a valve 9. In a braking system for motor vehicles,

for closing said vent for preventing the entrance'of an to said chamber, and means controlled by the-suction of said-engine for closing said valve and the throttle in said exhaust passage, and simultaneously opening the throttle in said intake.

10. In a braking system for motor vehicles, comprising an internal combustion engine, means for supplying an explosive mixture to said engine, an exhaust passage for said engine, a lever, and means c.0n-.

trolled by the suction of said engine for automatically substituting air for said'explosive mixture and for closing said exhaust passage upon a predetermined movement of said lever.

Signed at l Vilmington, in the county of Los Angeles, and State of California, this 17th day of April, A. D. 1925.

CHARLES L. STOKES. 

